Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV 26505, United States of America.
Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, WV 26505, United States of America.
Toxicol Appl Pharmacol. 2020 Dec 1;408:115256. doi: 10.1016/j.taap.2020.115256. Epub 2020 Sep 30.
Hydraulic fracturing ("fracking") is a process used to enhance retrieval of gas from subterranean natural gas-laden rock by fracturing it under pressure. Sand used to stabilize fissures and facilitate gas flow creates a potential occupational hazard from respirable fracking sand dust (FSD). As studies of the immunotoxicity of FSD are lacking, the effects of whole-body inhalation (6 h/d for 4 d) of a FSD, i.e., FSD 8, was investigated at 1, 7, and 27 d post-exposure in rats. Exposure to 10 mg/m FSD 8 resulted in decreased lung-associated lymph node (LLN) cellularity, total B-cells, CD4+ T-cells, CD8+ T-cells and total natural killer (NK) cells at 7-d post exposure. The frequency of CD4+ T-cells decreased while the frequency of B-cells increased (7 and 27 d) in the LLN. In contrast, increases in LLN cellularity and increases in total CD4+ and CD8+ T-cells were observed in rats following 30 mg/m FSD 8 at 1 d post-exposure. Increases in the frequency and number of CD4+ T-cells and NK cells were observed in bronchial alveolar lavage fluid at 7-d post-exposure (10 mg/m) along with an increase in total CD4+ T-cells, CD11b + cells, and NK cells at 1-day post-exposure (30 mg/m). Increases in the numbers of B-cells and CD8+ T-cells were observed in the spleen at 1-day post 30 mg/m FSD 8 exposure. In addition, NK cell activity was suppressed at 1 d (30 mg/m) and 27 d post-exposure (10 mg/m). No change in the IgM response to sheep red blood cells was observed. The findings indicate that FSD 8 caused alterations in cellularity, phenotypic subsets, and impairment of immune function.
水力压裂（“压裂”）是一种通过加压使地下含天然气的岩石破裂，从而提高天然气采收率的过程。用于稳定裂缝和促进气流的沙子会产生可吸入压裂砂尘（FSD）的潜在职业危害。由于缺乏对 FSD 免疫毒性的研究，本研究在大鼠中进行了全身吸入（每天 6 小时，持续 4 天）FSD8 的研究，即在暴露后 1、7 和 27 天。暴露于 10mg/m3 的 FSD8 会导致肺相关淋巴结（LLN）细胞减少，总 B 细胞、CD4+T 细胞、CD8+T 细胞和总自然杀伤（NK）细胞在暴露后 7 天减少。CD4+T 细胞的频率下降，而 B 细胞的频率在 LLN 中增加（7 和 27 天）。相比之下，在暴露后 1 天，大鼠吸入 30mg/m3 的 FSD8 后，LLN 细胞增多，总 CD4+和 CD8+T 细胞增多。暴露后 7 天，支气管肺泡灌洗液中 CD4+T 细胞、NK 细胞的频率和数量增加，同时总 CD4+T 细胞、CD11b+细胞和 NK 细胞增加（30mg/m3）。暴露后 1 天，脾脏中 B 细胞和 CD8+T 细胞数量增加。此外，NK 细胞活性在暴露后 1 天（30mg/m3）和 27 天（10mg/m3）时受到抑制。绵羊红细胞的 IgM 反应没有变化。研究结果表明，FSD8 导致细胞数量、表型亚群和免疫功能受损发生变化。
